Human cancer vaccines

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Three research projects were successfully studied. 1) We identified human osteosarcoma antigen PBF, papilloma-binding factor, from autologous CTL and osteosarcoma OS2000 line. PBF was expressed in a large part of soft part tumors as well as approximately 50 % tumors of epithelial origins, whereas it was not detected in normal part of tissues particularly in the protein level. These observations suggest that PBF could be utilized in the immunotherapy of cancers. 2) Reverse-immunological approaches of tumor antigens indicated that survivin could work as the tumor antigens. Particularly, survivin-derived 2Bpeptide induced CTL in many cancer patients in the HLA-A24 restricted manner. We are now underway the phase I clinical trials of this peptide in colon, breast, lung cancers, indicating that there are no adverse effects. Some of these patients demonstrated certain clinical responses such as reduction in tumor size in CT as well as in tumor marker levels. We are also underway the phase I clinical trials of HLA-A24-restricted B peptide derived from the SYT-SSX chromosomal translocation fusion product in synovial sarcoma patients. In this trial, there are no adverse effects, and two out of six patients indicated an increasing number of tetramer-positive CTL precursors. 3) We identified 35 novel tumor antigens by bioinformatics in silico approaches. Wet studies by using RT-PCR analysis confirmed that 7 out of 35 antigens have strict expression profiles as the tumor antigens.